(1) Field of the Invention
The present invention relates to the storage of recording media. More specifically, this invention is directed to apparatus for holding, and presenting upon command, recording media and especially to methods of and devices for releasably latching media receiving slider members in such magazines. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
(2) Description of the Prior Art
Magazines for storing recording media, such as magnetic tape cassettes, discettes and audio or video discs, are well known in the art. By way of example, a device for storing compact cassettes is disclosed in U.S. Pat. No. 4,046,255. The patented device includes a housing, at least a first transport slider member which is received in the housing and which is designed to accommodate the cassette, a spring for biasing the slider member to the ejected position where the cassette is presented for removal and use and a releasable locking mechanism for normally retaining the slider member in the inserted position in the housing against the bias of the spring. In the apparatus of U.S. Pat. No. 4,046,255 the locking mechanism includes a hook-like locking element which forms part of the slider member. This element is resiliently deformed during locking and remains in a stressed condition when in the locked position. The locking element will spring back to a release position during the unlocking, i.e., ejection, procedure. In the interest of minimizing manufacturing cost, it is customary to fabricate the locking element from a plastic material. However, this results in unreliable operation since the plastic materials which are otherwise suitable for use have a tendency to cold flow as a result of constantly applied stresses. Any such cold flow will result in the spring bias of the locking element being lost. Further, such normally stressed plastic locking elements will fail at high temperatures. Since recording media storage devices are often for installed in motor vehicles, where temperatures on the order of 80.degree. C. must be taken into consideration, apparatus of the type disclosed in U.S. Pat. No. 4,046,255 have been found to be unsuitable for such usage.
Another example of a storage device for compact cassettes may be seen from FIGS. 5-8 of U.S. Pat. No. 3,995,921. The storage device of this patent does not employ a slider member. Rather, a spring arrangement directly biases the cassette in the direction of ejection. The spring arrangement is locked at a guide projection of the housing of the device and remains stressed toward the unlocked position. The apparatus of U.S. Pat. No. 3,995,921 has the disadvantages that the cassette is inadequately protected and the spring arrangement is relatively complicated and, therefore, expensive. Further, again considering the possibility of motor vehicle installation, the locking mechanism is unreliable, and particularly is not resistant to vibration as a result of the very small surface areas which are engaged in the locked position.
Yet another device for storing compact cassettes is disclosed in U.S. Pat. No. 3,836,222. The device of this patent has a comparatively complicated locking mechanism wherein the steps of locking and unlocking do not automatically follow alternatively one after the other as is desirable, particularly in a motor vehicle installation where the device should be capable of operation without prolonged eye contact. In the apparatus of U.S. Pat. No. 3,836,222 the locked or unlocked condition depends upon the degree of insertion travel of a transport slider member and, accordingly, the locking mechanism is somewhat unreliable in addition to being difficult to use.